U.S. patent number 6,657,164 [Application Number 10/274,362] was granted by the patent office on 2003-12-02 for customizable heated insole.
This patent grant is currently assigned to Hotronic International Limited. Invention is credited to Albin G. Koch.
United States Patent |
6,657,164 |
Koch |
December 2, 2003 |
Customizable heated insole
Abstract
Heated insoles are presented in the form of separate packages
that will combine into a kit to make a heated insole for footwear.
One package contains a heating assembly made of a heating element,
a flexible power cable ending in an electrical connector, and
(optionally) a power pack that contains a rechargeable battery, a
rheostat, and a mating electrical connector. The other package
contains a flexible, cushioned insole having a sealable opening and
guide channel on the bottom. Once a suitable sized insole is
selected, the heating element is inserted into a sealable opening
in the insole that is dimensioned to receive the heating element
and sealed therein. This kit and manner of construction allows
retailers to stock fewer heating elements than insole sizes so as
to reduce inventory costs.
Inventors: |
Koch; Albin G. (Davos,
CH) |
Assignee: |
Hotronic International Limited
(Davos, CH)
|
Family
ID: |
29549754 |
Appl.
No.: |
10/274,362 |
Filed: |
October 21, 2002 |
Current U.S.
Class: |
219/211;
36/2.6 |
Current CPC
Class: |
A43B
7/04 (20130101); A43B 17/00 (20130101); A43B
17/006 (20130101); H05B 3/342 (20130101); H05B
2203/017 (20130101); H05B 2203/036 (20130101) |
Current International
Class: |
A43B
7/00 (20060101); A43B 7/04 (20060101); A43B
17/00 (20060101); H05B 3/34 (20060101); H05B
001/00 () |
Field of
Search: |
;219/211,523,528
;36/2.6,43 ;607/111 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Walberg; Teresa
Assistant Examiner: Fastovsky; L
Attorney, Agent or Firm: Roylance, Abrams, Berdo &
Goodman, LLP
Claims
What is claimed is:
1. Electrically heated thermal insole kits containing: a. a
flexible, electrically powered resistance heating assembly having a
heating element electrically bonded to an extended flexible power
cable and which terminates in a power supply connector, and b. a
flexible, cushioned footwear insole of extended length with a toe
end, a heel end, and having an upper layer bonded with an adhesive
to a cushioned bottom layer wherein the cushioned bottom layer
exhibits a flap, an associated opening, and an external channel
extending from the flap opening to the heel end of the insole for
guiding the flexible power cable along the length of the insole to
the heel end of the insole.
2. The kit of claim 1 wherein said opening is dimensioned to
receive the heating element of the heating assembly.
3. The kit of claim 1 wherein one side of said flap is coated with
an adhesive which is covered with a removable barrier film whereby
insertion of the heating element into said opening, removal of the
barrier, and closure of the flap opening will seal the heating
element between the upper layer and the cushioned bottom layer.
4. The kit of claim 1 wherein said insole exhibits a flat
longitudinal side profile.
5. The kit of claim 1 wherein said insole exhibits a contoured
longitudinal side profile.
6. The kit of claim 1 wherein said heating element is generally
circular in shape.
7. The kit of claim 1 further comprising a battery power pack
having a rechargeable battery and a mating power supply
connector.
8. The kit of claim 1 wherein said insole further exhibits markings
at the toe end for reducing the size of said insole.
9. A method for fitting an electrically powered, heated insole to a
user comprising the steps of: a. selecting a cushioned insole
dimensioned for a particular range of shoe sizes and bearing a
guide at a toe end of said insole for reducing said insole to a
smaller size, wherein said insole exhibits an extended length and
width with a toe end and a heel end, b. inserting a resistance
heating element into an opening in a bottom side of said insole and
aligning said element therein whereby an extended flexible power
cable extends out of said opening and across the length of said
insole in a channel formed in a bottom side of said insole, c.
removing a barrier film from an adhesive layer on a flap shaped to
seal said heating element in said opening, and d. sealing said
heating element within said insole.
10. A method according to claim 9 further comprising: trimming said
insole to a desired size.
11. A method for making a footware insole able to receive a thermal
heating element, said method comprising the steps of: a. cutting a
flap opening in a first cushioned laminate having at least one
layer of cushioning foam, at least one layer of adhesive, and at
least one barrier film covering said adhesive layer, b. laminating
the first laminate sub-assembly to a second laminate sub-assembly
by adhesion with adhesive on said first laminate sub-assembly that
is not protected by said barrier film thereby forming an opening
pocket between the first and second laminate sub-assemblies that
can be accessed through said flap opening.
Description
FIELD OF THE INVENTION
The invention relates to an electrically heated warming system for
use in cold environments using rechargeable batteries as a source
of electrical energy.
BACKGROUND OF THE INVENTION
Many sports and activities are conducted outdoors under cold and
possibly harsh conditions. Examples include snow skiing, hunting,
ice skating, ice fishing, etc. Many occupations also involve
exposure to similar conditions. In each circumstance, the body will
respond to cold temperatures by directing blood flow to maintain
core body temperature even though the extremities, hands and feet,
may suffer discomfort.
A variety of products have been sold as sources of warmth for the
extremities that may be used in boots, mittens, and gloves. Some of
the products rely on slow chemical reactions that produce a range
of heat output based on exposure to oxygen. Such products can be
made inexpensively but are bulky and require a certain minimum rate
of air flow or volume of air for proper operation. Chemical heat
sources are not well suited for use in form fitting ski boots and
typically are not designed to be reusable once depleted.
Another type of product relies on a battery current flowing through
a resistive heat element to produce heat in the vicinity of the
resistive element. Some products have a fixed current flow. Others
have a variable rate of current flow. Both types of units, however,
use batteries connected to the resistive element by a flat wire so
that the battery pack is located outside the article of clothing.
Battery packs for ski boots are often clipped on the back or
outside of the boot by a spring clip.
Current versions of commercially available electrically heated
insoles are thin and flat with an electrical heating element
adhered at the forward end (at optimal toe placement) between a top
layer of thin material and a cushioned bottom layer. See, U.S. Pat.
No. 5,140,131 whose disclosure is herein incorporated by reference.
A flat electrical cable ran beneath the insole from the heating
element to the trailing edge beneath the cushioned layer, up the
back of the boot between the inner boot and outer shell, and out
the top to a battery clipped outside the boot. It was thought that
a thin, flat insert, i.e., one free of anatomical features for
providing contoured foot support, would be more desirable to avoid
interference with the existing contoured insoles specifically made
for relatively highly engineered ski and work boots. Adhesion of
the heating element between the insole layers assured correct and
secure placement of the element.
Unfortunately, there are some disadvantages to the conventional
electrically heated thermal insoles. One is the trend towards more
form-fitting ski boots that may become uncomfortable if even a thin
thermal insole is added inside the foot chamber. Such close
quarters in the foot chamber may also allow the users with some
foot shapes to feel the flat cable running the length of the
insole. Removal of the engineered insole reduces comfort. It would
be desirable to have a heated insole for shoes, boots, and other
footwear used in cold temperatures that could be customized to meet
the size, shape, and support needs of almost any user for almost
any activity.
What it gains in manufacturing quality and consistency with the
thermal element, however, the conventional electrically heated
thermal insole loses in flexibility. Retailers need to stock one
complete thermal insole for each size boot they expect to sell.
Because the thermal element and attached electrical cable is the
more expensive component, ski boot retailer will need to make a
significant investment in thermal insole inventory to be considered
fully stocked for the entire range of ski boot sizes through any
designated period in the skiing season. The user is also faced with
an impossible choice: risk reduced comfort and fit for extended
skiing time with the thermal insole rather than the original
engineered insole for the boot.
It would be desirable to have a method for supplying an inventory
of electrically heated thermal insole that could be stocked in a
variety of sizes and in a quantity sufficient to supply cyclical
business demands with minimum capital investment in inventory.
It would also be desirable to have an electrically heater thermal
insole design that would exhibit a construction design that would
provide the user and the retail seller with a quality product and
options not available with conventional pre-constructed thermal
insoles.
SUMMARY OF THE INVENTION
Electrically heated thermal insoles according to the invention are
in the form of a kit made of separate packages for (a) a flexible,
electrically powered resistance heating assembly that contains the
heating element electrically bonded to a flexible power cable which
terminates in a power supply connector, and (b) a flexible,
cushioned footwear insole of extended length with a toe end and a
heel end and having an upper layer bonded to a cushioned bottom
layer, wherein the cushioned bottom layer exhibits a flap opening
and a channel extending from the flap opening to the heel end of
the insole for guiding the flexible power cable along the length of
the insole. The inside of this flap is dimensioned to receive the
heating element of the heating assembly and is covered with an
adhesive which is, in turn, covered with a removable barrier film
whereby insertion of the heating element, removal of the barrier,
and closure of the flap opening will seal the heating element in
the insole.
Electrically heated thermal insoles according to the invention are
provided in the form of separate packages for the universally-sized
heating assembly and for the sized insole. This separation of
heating element and insole allows the retailer to stock a
relatively few number of heating elements and a wide variety of
relatively inexpensive sized insole units which may have the
conventional flat profile for general use or may be contoured for
an engineered fit for a particular type of footwear or foot shape.
When the proper insole is selected, the user or the retailer
install the heating element within the insole by introducing the
heating element into the opening created by the insole flap,
removing the barrier film to expose the adhesive, and sealing the
heating element within the insole. When the heating element and
power cord are aligned properly, the power cord lies in an outer
channel formed into the bottom outside surface of the cushioned
insole and extends from the embedded heating element to the heel
end of the insole, up the back of the shoe or boot, and to an
electrical connector suitable for forming a mated electrical
connection with a control pack containing a battery, the mating
electrical connector, and, preferably, an adjustable rheostat.
The heated insole kit and components of the invention offer
advantages not previously available. With the kit of the present
invention, retailers can reduce their investment in inventory by
stocking a relatively limited number of universally-sized heating
element assemblies and a wide variety of insoles of different sizes
and shapes for more a precise matching to the user's particular
needs. Users receive a heated insole product that fits better and
is better suited to their cold weather sporting needs.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows the kit of the invention containing, as separate
components, a cushioned insole, a heating assembly, and a battery
pack. An associated recharger for the battery pack is not
illustrated.
FIG. 2 depicts a cross sectional view of a typical heating element
and associated power cord.
FIG. 3 is a cross sectional view of the toe end of an insole with
an open flap with adhesive for receiving and securing the heating
element therein.
FIGS. 4 and 5 illustrate a cushioned insole having anatomically
supportive contours formed therein.
FIGS. 6 and 7 show a cushioned insole having a flat cross sectional
profile with indentations formed into the insole for adjusting the
size of the insole.
DETAILED DESCRIPTION
Heated insoles according to the invention are made available in the
form of a kit of two or more discrete units. One unit contains the
heating assembly, and the other contains the flexible, cushioned
footwear insole. A power pack assembly can be combined with one of
these packages or made available as a third unit. These units can
be grouped or made available individually for reduced inventory
costs and greater flexibility for the users in selecting a heated
insole suitable for the particular needs of the user.
See, U.S. Pat. No. 6,218,644 whose disclosure is incorporated
herein by reference.
Briefly described, the heating element comprises a resistor with
electrical leads and a distributor made of a top layer, a central
layer, and a bottom layer which are laminated together. The
resistor is a conventional electrical component used in heated
insoles and whose sole function is to convert electrical energy
from the direct current of a battery into sensible heat that is
laterally distributed over the target foot surfaces (usually the
toes and front of the foot). The resistor is typically used in the
form of an integrated circuit or microchip whose heat output is
proportional to the applied voltage.
The top and bottom layers of the distributor are flexible, highly
heat conductive, and formed of a metal having a heat conductive
coefficient within the range from about 80-100. Copper is a
particularly preferred material for the top and bottom layers.
The center layer is a flexible carrier that provides structural
integrity to the heating element and insulates the top and bottom
layers, both electrically and thermally. A preferred central layer
is made of a fiberglass laminate having a low heat conduction
coefficient, e.g., a coefficient of less than 1, preferably within
the range from about 0.20 to about 0.30. The central layer, acts as
a momentary heat dam and storage structure, which aids in
distributing the heat across the surface of the heating element for
warming of the user's toe area.
Advantageously, the heating element can also comprise a first thin
coating of water-resistant material to seal the heating element
against moisture and the problems associated with an electrical
circuit in close proximity to the human foot. These coatings resist
corrosion of the top and bottom layers and can be transparent, but
will not degrade under heating nor interfere with heat conduction
of the heating element. A variety of lacquers and sealants are
commercially available that will provide a flexible, water
impervious coating for the electrical contacts and surfaces.
The power cable is preferably flat, has two conductive wires, is
highly flexible, and is cut to a sufficient length to extend from
the toe of a large boot insole, across the bottom in a channel
formed into the bottom of the insole, up the back of a relatively
tall ski boot, with enough remainder to allow a terminating
electrical connector to be attached to a battery pack located in
the upper half of the total height of the ski boot. A power cable
length within the range of about 50-80 cm should be generally
adequate. If desired, one or more wires or high tensile fibers can
be secured to or molded into the power cable as a structural member
for bearing the tensile load forces placed on the power cable in
normal use.
The matable electrical connector at the end of the power cable can
take virtually any configuration that is able to connect with the
battery pack to form a reasonably firm, water resistant connection.
Suitable connections can include dual prong male/female connectors,
twist-to-lock connections, threaded fittings, and the like.
The cushioned insole is a composite having a relatively thin top
layer of soft woven or nonwoven material that readily conducts heat
and a relatively thicker bottom layer of one or more cushioning
materials that do not readily conduct heat. The cushioning material
can be formed as a relatively flat surface generally shaped as
footprint or may be formed to exhibit surface contours and
engineered support surfaces that provide additional support to the
user's foot.
The battery pack unit includes a rechargeable battery power supply
in a water tight enclosure with a rheostat for adjusting the
electrical output and an electrical connector that will mate with
the connector on the flexible power cable. The particular type of
battery can include any form of rechargeable battery that is
sufficient to provide adequate power output in ambient temperatures
of 20.degree. F. (-6.degree. C.) or less. Exemplary materials
include nickel cadmium, nickel metal hydride, and the like.
The present invention represents a new method that allows the needs
of the user to be matched with the best heated insole product
without additional cost to the retailer. In particular, the
retailer can select and collect an inventory of relatively
inexpensive insole units of a wide variety of sizes or size ranges
and flat or supportingly contoured configurations.
Each insole will have an opening and a correspondingly shaped,
adhesive covered flap to receive the heating element of a heating
assembly. A barrier film over the adhesive on the flap prevents the
flap from sealing the opening in the insole. The heating element is
inserted into the insole opening, usually with the resistance chip
facing away from the user's foot and extending into the cushioning
material of the covering flap,so that the power cable attached to
the heating element extends out of the opening and into a channel
formed into the bottom surface of the insole. This channel extends
longitudinally over the length of the insole from the opening to
the heel end of the insole and is laterally positioned on the
insole to prevent both twisting of the power cable and lateral
movement outside the channel when the user is engaging in physical
activities that may involve fairly fast or significant foot
movements.
When the barrier film is removed to expose the adhesive, the flap
is lowered over the heating element to seal the heating element
within the insole opening. Because the adhesive will be in contact
with an electrical connection, the adhesive should not be
electrically conductive and is desirably water resistant to provide
additional protection against contact of moisture with the power
connection for the heating element.
The insole can be trimmed to reduce the length and/or width or both
either before or after installation of the heating element within
the opening. Preferably, any adjustments in particular dimensions,
as for a custom fit, or for adjusting the insole to a smaller
standard shoe size will occur before the heating element is
installed. The delay provides additional safeguards for the heating
element in the event of trimming errors and saves the cost of the
heating element in the event of any trimming errors.
The invention is conveniently described with reference to the
attached figures and in the context of an insole insert suitable
for a skiing boot. It will be understood that similar structural
features and components will be designated with the same reference
numeral and that all references to a "boot" will also be applicable
to other footwear in which the heated insole of the invention is
used. The relative terms "top" and "bottom" will be used to
describe a spatial orientation generally considered to be most
comfortable in use. It is possible, however, to use the insoles in
an opposite orientation: in such a circumstance, the terms "top"
and "bottom" will refer to their opposite surfaces.
Insole 1, heating assembly 2, and battery pack 3 are shown as
separate, unassembled components. Insole 1 is a generally
foot-shaped configuration with a toe region 10, midsole region 12,
and heel area 13. The view shown in FIG. 1 is toward the bottom of
insole 1.
Flap 4, corresponding opening 5, and channel 6 are formed in the
bottom of insole 1. Opening 5 is dimensioned to receive resistance
heating element 7 and become secured therein when barrier film 8 is
removed and flap 4 is closed. It will be understood that opening 5
and the corresponding flap 4 can be formed with many possible
shapes provided that the dimensions thereof are sufficient to
receive heating element 7 and secure it when sealed. When heating
element 7 is secured in opening 5, power cable 9 extends from
opening opened 5 at toe region 10 into and down the length of
channel 6 to the heel end 11 of insole 1 and will further extend up
out of the boot and into a mating electrical connection with
battery pack 3 that is secured to the outside of the user's boot.
This separation of components and insole design allows users or
retailers to select an insole size and design which is later
combined with a heating assembly 2 in an aligned configuration to
provide a good fit with correct installation of the heating
assembly 2 within insole 1.
FIG. 2 illustrates a laminated structure for heating element 7. Top
layer 20 and bottom layer 21 are made of a heat conductive
material, typically a metal like copper or a metallic alloy, that
can be formed or deposited on insulative carrier 22. Resistive
heating chip 23 receives direct current electrical energy via power
cable 9 and produces sensible heat that is laterally distributed
via top layer 20 and bottom layer 21 across and anywhere within the
toe area i.e., the ball of the foot and forward to, and including
the toes. It is intended that heating chip 23 will be mounted
within opening 5 so that heating chip 5 is away from the user's
foot and extends into the cushioned material 30 of insole 1.
FIG. 3 presents an enlarged cross sectional view of the toe region
10 of insole 1. Insole 1 is preferably made of a multi-layer
construction adhered to form an integral laminate that includes
(from sole bottom to sole top) firm foam layer 30 of adequate
density and rigidity to provide support for a user's foot and
structural integrity to the shaped insole, first covering fabric or
nonwoven layer 31, second foam layer 32 of open cell foam or
equivalent with lesser density than firm foam later 30 but adequate
to provide comfort and thermal insulation against the heat loss
downwardly thru firm foam layer 30, third foam layer 33 of open
cell foam or equivalent with a thickness and density best suited
for user comfort and providing less thermal insulation than second
foam layer 32, and top layer 34 of woven or nonwoven fabric.
Adhesive layers 35 may be the same or different adhesive
composition and are used to laminate the various layers together.
Preferably, adhesive layers 35 are the same environmentally
acceptable self adhesive that is chemically compatible with the
materials used in successive layers of the laminate.
Barrier film 8 covers adhesive layer 35 in region 36 on second foam
layer 32 of flap 4 and prevents contact with adhesive in region 37
on third foam layer 33 until barrier film 8 is removed. When
heating element 7 is formed so that it is smaller than and does not
completely fill opening 4, adhesive in region 36 bonds to adhesive
in region 37 around the perimeter of heating element 7 and seals
heating element 7 within opening 5. Optionally and as shown in FIG.
3, barrier film 8 can be folded to cover the exposed laminate edge
38 to facilitate insertion of heating element 7 into opening 5.
FIGS. 4 and 5 illustrate insole 1 having insole 1 formed with a
plurality of anatomically supportive surface rises 40 and valleys
41. Insole 1 can be formed with multiple areas of differing
densities for enhanced user comfort. For example, arch area 42 may
be formed to exhibit a lower or higher density than heel cushioning
43.
FIGS. 6 and 7 depict insole 1 with grooves 60, 61 formed into toe
region 10 for the purpose of providing guidance in the proper trim
lines for reducing the size of insole 1 by one standard shoe size
(grooves 60) or two standard shoe sizes (grooves 61). When insole 1
is formed in a flat profile, as shown in these figures, grooves 62
and 63 may be formed in heel area 13 to provide guidance for those
users who need to narrow or shorten the heel area. Instead of
physical grooves formed into the material, size adjustment markings
can also be imprinted on the surface of insole 1 on either the top
or bottom surfaces.
In any event, the number of sizes by which insole 1 can be adjusted
is functionally limited by the ability of h eating element 7 to be
positioned near the user's toes and to distribute heat across the
toe area. Too much insole length on the toe end of opening 5 will
not permit an adequate amount of heat to reach the user's toes and
may adversely affect comfort in cold situations. Thus, it is
generally advised that insole 1 be modified no more than one or two
sizes from the original size.
Insole 1 is preferably formed with a plurality of laminating steps
and/or sub-steps. An exemplary combination of parallel process
steps includes the following steps: the formation of a first
laminate sub-assembly made with first and second foam layers 30, 32
on either side of fabric or nonwoven layer 31. This first laminate
sub-assembly is then coated with adhesive layer 35 over second foam
layer 32 and covered in its entirety with one or more pieces of
barrier film 8. One or more die cutting steps then cuts flap 4 into
and through the first laminate sub-assembly including barrier film
8. Barrier film 8 is then removed from the adhesive covered surface
of the first laminate sub-assembly except for that portion of
barrier film 8 covering region 36.
The first laminate sub-assembly having flap 4 cut therein is then
laminated to a second laminate sub-assembly that comprises third
foam layer 33 and top layer 34. Preferably, the first laminate
sub-assembly is provided with machine-readable key markings or
indicia that allow the machine to determine where flaps 4 have been
cut into the first sub-assembly so that insoles can be cut for
proper positioning of flap 4 on insole 1 after the fist and second
sub-assembly laminates are joined.
* * * * *